1. Field of the Invention
The present invention relates to a light detecting device.
2. Description of Related Art
JP-A-2002-500769 discloses a light detecting device having a light introducing member and a light receiving element. A headlight of a vehicle is controlled based on an intensity of light detected by the light detecting device. The light introducing member introduces a predetermined light passing through a windshield of the vehicle. The light receiving element receives light emitted from the light introducing member. A light emitting face of the light introducing member has a convex lens shape. A light receiving face of the light receiving element is arranged at a position corresponding to a light-collecting spot of a focus of the light introducing member.
An angle of the windshield relative to the vehicle is different among kinds of the vehicle. Due to the difference in the angle of the windshield, the light receiving face of the light receiving element and the focus of the light introducing member may have a position deviation. In this case, the predetermined light may not be detected by the light receiving element. Therefore, it is necessary to adjust the position of the light receiving element or the focus of the light introducing member relative to each kind of the vehicle.
JP-A-2005-31016 discloses a light detecting device. A light emitting face of a light introducing member of the light detecting device is processed, such that a curvature radius of the light emitting face is partially changed. Thus, a light-collecting spot of a focus of the light introducing member can have a large diameter. In this case, even if a position deviation is generated between the light receiving element and the focus of the light introducing member, the predetermined light can be detected by the light receiving element.
However, highly precise processing is required for the light detecting device of JP-A-2005-31016. Moreover, there is a limit for increasing a size of the light-collecting spot by changing the curvature radius of the light emitting face. Therefore, if the angle of the windshield has a large variation among the kinds of the vehicle, a position deviation may be generated between the light-collecting spot and the light receiving face. In this case, the predetermined light may not be detected by the light receiving element.